1. Field
The described technology relates generally to an organic light emitting diode (OLED) display and a manufacturing method thereof.
2. Description of Related Art
An organic light emitting diode (OLED) display includes an organic light emitting element and a thin film transistor as a driving element that drives the organic light emitting element.
In a thin film transistor manufacturing process, remnants and contaminants remain in or at a surface after each process. The remnants and the contaminants distort an element structure and deteriorate an electric characteristic, thereby deteriorating performance and reliability of the element. The remnants and the contaminants include organic contaminants, particles, metal impurities, and a native oxide, and they should be eliminated through a cleansing process.
A polycrystalline silicon layer used as a semiconductor layer in the thin film transistor is formed by crystallizing amorphous silicon with thermal treatment. The native oxide is formed when the polycrystalline silicon layer is formed, and a contaminant like a metal impurity may be included in the native oxide while the native oxide is growing. The native oxide deteriorates the performance of the polycrystalline silicon layer and increases contact resistance. The metal impurity may diffuse into the polycrystalline silicon layer, which may cause a failure in the element during a post heat treatment.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.